I Recently Had A Knee Replacement And Since The Surgery

I recently had a knee replacement and since the surgery Aug 3, I have been having circulation problems in the replacement leg from the knee down. I went to a Vein clinic and they couldn't find anything significant, but the doctor noted a difference in skin texture, color, etc. I have been checked for blood clots twice with nothing found. There is tenderness in the chin, calf and a very painful spot just below the knee on the right side. O not sure what to do next. The orginal doctor thought it was just swelling which it does occasionally, but it is still sensitive even when it is not swollen.